Intensity- and Duration-Based Options to Regulate Endurance Training

Abstract

The regulation of endurance training is usually based on the prescription of exercise intensity. Exercise duration, another important variable of training load, is rarely prescribed by individual measures and mostly set from experience. As the specific exercise duration for any intensity plays a substantial role regarding the different kind of cellular stressors, degree, and kind of fatigue as well as training effects, concepts integrating the prescription of both intensity and duration within one model are needed. An according recent approach was the critical power concept which seems to have a physiological basis; however, the mathematical approach of this concept does not allow applying the three zones/two threshold model of metabolism and its different physiological consequences. Here we show the combination of exercise intensity and duration prescription on an individual basis applying the power/speed to distance/time relationship. The concept is based on both the differentiation of intensities by two lactate or gas exchange variables derived turn points, and on the relationship between power (or velocity) and duration (or distance). The turn points define three zones of intensities with distinct acute metabolic, hormonal, and cardio-respiratory responses for endurance exercise. A maximal duration exists for any single power or velocity such as described in the power-duration relationship. Using percentages of the maximal duration allows regulating fatigue, recovery time, and adaptation for any single endurance training session. Four domains of duration with respect to induced fatigue can be derived from maximal duration obtained by the power-duration curve. For any micro-cycle, target intensities and durations may be chosen on an individual basis. The model described here is the first conceptual framework of integrating physiologically defined intensities and fatigue related durations to optimize high-performance exercise training.

Functional Threshold Power in Cyclists: Validity of the Concept and Physiological Responses

“…A previous study has used the mean PO in a 20-min TT is used for training intensity prescription and regular performance monitoring [23]. The obtained value might not necessarily represent the boundary between the heavy-and the severe-intensity domain [13,18], but this test is more practical than a 60-min TT and does not involve the burden of multiple MLSS assessments. Although this approach does not solve the issue of training-zone systems that do not directly compare [26], 20-min TT performance is reliable [24] and sensitive to training adaptations [22] and cycling ability [6].…”

“…The lactate threshold (LT) model distinguishes three exercise-intensity domains in which the boundaries are the aerobic threshold (LT 1 ) and the anaerobic threshold (LT ) [13,18]. In sports science, training intensity prescription is often based upon target intensity zones defined according to this model [13,18].…”

“…The lactate threshold (LT) model distinguishes three exercise-intensity domains in which the boundaries are the aerobic threshold (LT 1 ) and the anaerobic threshold (LT ) [13,18]. In sports science, training intensity prescription is often based upon target intensity zones defined according to this model [13,18]. However, most endurance athletes cannot rely on formal laboratory testing to determine LTs and therefore adopt five-zone systems with anchor points defined somewhat arbitrarily, for example, based upon percentages of maximal heart rate (HR max ) [26].…”

Estimation of lactate threshold with machine learning techniques in recreational runners

“…Lactate threshold is the exercise intensity at which the concentration of blood lactate begins to significantly increase compared to the values at resting and is closely related with the anaerobic threshold. This is considered an essential parameter when assessing performance of elite and recreational runners [5,6], prescribing training intensities in endurance sports [7,8] and can be useful for athlete internal load monitoring [9]. Furthermore, nowadays it is fully demonstrated that the lactate threshold is more decisive for endurance sports performance than other variables such as the maximum consumption of oxygen or the running economy [10,11,12,13].…”

A heuristic approach for lactate threshold estimation for training decision-making: An accessible and easy to use solution for recreational runners

“…The lactate threshold (LT) is the exercise intensity at which the concentration of blood lactate begins to exponentially increase compared to the values at resting. This physiological indicator is considered essential for endurance sports performance from (at least) three different perspectives: monitoring training by assessing the physical condition from an endurance performance perspective [1]; prescribing exercise intensity [2]; and performance estimation [1].…”